Java, dealing with XML and JPA Annotated Classes

I use xjc to compile XSD files to Java Classes, and want to edit/extend them to make them persistable through JPA.

I cant figure out what the best “Coupling?” would be and how to organize it, if I modify the xjc compiled Classes to be persistable, I would lose the Ability to recompile the XSD if there are any changes.

Even if I didn’t need to recompile, in some cases, I still wouldn’t be able to serialize/deserialize Data that was collected before my Schema changed.

I don’t want to completely “decouple”, since I want to keep the ability to Persist the imported XML Object with just a few lines of code (not having to write a sort of “converter” for each XML Entity).

Has anyone been faced with the same issue? How did you manage to solve it.